Method and apparatus for manufacturing high-purity hydrogen storage alloy Mg2Ni

ABSTRACT

The present invention provides a method and apparatus for manufacturing high-purity hydrogen storage alloy Mg 2 Ni applicable to industry and capable of manufacturing continuously. First, raw materials of magnesium-nickel with weight percentage of nickel between 23.5 and 50.2 are heated, melt, and mixed uniformly. Cool the magnesium-nickel liquid and control the temperature to be above the solidification temperature and below the liquification temperature in the phase diagram of magnesium-nickel. By making advantage of segregation principle in phase diagrams, solid-state high-purity γ-phase Mg 2 Ni hydrogen storage alloy is given. The residual waste magnesium-rich liquid in the crucible is poured to another independent crucible, and switch with the position of the crucible originally containing the γ-phase Mg 2 Ni hydrogen storage alloy. Then, new raw materials of magnesium and nickel are added and heated. Repeat the smelt steps described above continuously, and a continuous manufacturing method is introduced. After the original crucible is cooled, the solid substances at the bottom of the crucible can be tapped down without further special treatments. Then high-purity γ-phase Mg 2 Ni hydrogen storage alloy with atomic ratio of 2:1, no other phases, and with excellent hydrogen absorption-desorption dynamics is given.

FIELD OF THE INVENTION

The present invention relates generally to a hydrogen storage technologyfor new energies, and particularly to a method and apparatus formanufacturing high-purity hydrogen storage alloy Mg₂Ni.

BACKGROUND OF THE INVENTION

Owing to substantial growth of usage in fossil energy while which energyis drying up gradually, to pernicious substances harmful to human bodiesproduced by extensive application of fossil energy, such asSO₂—CO—NO_(x), and to global climate changes caused by the greenhouseeffect due to considerable quantity of exhausted CO₂, the world isdevoted to the development of new energy technologies. In particular,hydrogen energy is planned to be one of the major energies in the futureby the International Energy Agency (IEA), because the byproduct thereofis water only, without CO₂, which completely prevents pollution and thegreenhouse effect. However, in practical applications, due to the lightmolecular weight of hydrogen, the storage volume will be immensely huge.Though super-high pressure can be adopted for storage, safety will beanother issue.

The problems of storage density and safety of hydrogen are not solveduntil 1980 when the hydrogen storage alloys that can stores hydrogen insolid state is introduced. Nevertheless, the hydrogen storage density ofcurrent commercial hydrogen storage alloys, includingtransition-metal-based hydrogen storage alloys AB₂ orrare-earth-metal-based hydrogen storage alloys AB₅, is still too low,less than 2.0% in weight. Thereby, the research and development ofhigh-capacity hydrogen storage alloys is the current internationaltrend. Particularly, magnesium-based hydrogen storage alloys areregarded as potential hydrogen storage alloys due to their low costs inraw materials. However, because pure magnesium is very active, thesurface thereof tends to form an oxidation layer that can blockabsorption of hydrogen molecules, and hence affect diffusion rate ofhydrogen atoms on the surface of alloys. As a result, pure magnesium isdifficult to be activated and has bad hydrogen absorption-desorptiondynamics. In addition, the temperatures of hydrogen absorption anddesorption are too high. Accordingly, it cannot be developed to be apractical hydrogen storage alloy.

Regarding to the issue of bad hydrogen absorption-desorption dynamics ofpure magnesium, by many researches, it is discovered that by addingnickel with catalyzing effect, the reaction rate of hydrogenabsorption-desorption in the hydrogen storage alloy Mg—Ni can beimproved, and the initial activation properties is catalyzed as well. Inthe Mg—Ni-based hydrogen storage alloys, Mg₂Ni in the γ-phase has thefastest activation reaction rate and the best hydrogenabsorption-desorption property.

Because the melting points of magnesium (649° C.) and nickel (1455° C.)differ greatly, melting tends to be ununiform, which would result inununiformity in composition of the hydrogen storage alloy. In addition,the vapor pressure of magnesium is high, thereby magnesium is easy tovaporize during melting, which causes severe deviation in initialcomposition, and excess eutectic structure and formation of the β-phaseMgNi₂, which is incapable of absorbing hydrogen. In order to solve theproblem the severe deviation in composition during melting as describedabove, next-generation vacuum induction furnaces are introduced.However, although the vacuum induction furnaces are equipped within-situ inspection, for the hydrogen storage alloy Mg—Ni, owing to itsnatural characteristic in the phase diagram, the melt liquid of Mg—Nistill cannot give 100%-pure γ-phase Mg₂Ni after solidification, even thecomposition of magnesium and nickel are controlled to be accurately 2:1via the most precise in-situ inspection function. This is becauseaccording to the binary equilibrium phase diagram of magnesium andnickel, in such a composition, far above the melting point 761° C. ofthe γ-phase Mg₂Ni, the β-phase MgNi₂, which has a meting point of 1147°C. and is incapable of absorbing hydrogen, has solidified andprecipitated first. Besides, because the composition of the β-phaseMgNi₂ has much more nickel than the γ-phase Mg₂Ni, the residual Mg—Nimelt liquid yet solidified deviates from the original composition of theγ-phase Mg₂Ni with a magnesium-to-nickel atomic ratio of 2:1, andbecomes a magnesium-rich state. The Mg—Ni melt liquid in themagnesium-rich state, according to the binary equilibrium phase diagramof magnesium and nickel, not only will form the γ-phase Mg₂Ni if thetemperature is lower than 761° C. in the present composition, but alsowill give an eutectic structure including the pure-magnesium phase atthe eutectic temperature of 507° C. That is to say, even the macroscopiccomposition complies with the proportion of the γ phase, the microscopicstructure thereof includes the β-phase MgNi₂ and the solid solutionphase of pure-magnesium in the γ-phase Mg₂Ni. Thereby, the smelt methodaccording to the prior art cannot be used for preparing high-purityhydrogen storage alloy Mg₂Ni with fast activation reaction rate and withexcellent hydrogen absorption and desorption properties.

Accordingly, the authors of the present invention make advantage of thesegregation principle in physical metallurgy, in a broad range ofcomposition and in low temperatures (far lower than the melting point ofpure nickel), and propose a simple apparatus for continuouslymanufacturing high-purity hydrogen storage alloy Mg₂Ni.

SUMMARY

An objective of the present invention is to provide a method andapparatus for manufacturing high-purity magnesium-nickel hydrogenstorage alloy without the need of precisely controlling the compositionof magnesium and nickel in the magnesium-nickel alloy.

Another objective of the present invention is to provide a method andapparatus for manufacturing high-purity magnesium-nickel hydrogenstorage alloy, which can recycle the residual magnesium-rich liquidafter the precipitation reaction and continuously manufacturehigh-purity magnesium-nickel hydrogen storage alloy according to themethod provided by the present invention.

In order to achieve the objectives described above, the presentinvention provides a method and apparatus for manufacturing high-puritymagnesium-nickel hydrogen storage alloy. The apparatus comprises avacuum chamber with a material feeding tube, a first crucible, a heatingdevice, a stirring device, and a second crucible. First, put the rawmaterial of pure magnesium into the first crucible, and place the firstcrucible into the vacuum chamber gassed with an inert gas. Then, use theheating device to heat the magnesium raw material until it meltscompletely into a magnesium liquid. Next, use the material feeding tubeto add slowly pure nickel powders to the first crucible with themagnesium liquid, and use the stirring device to stir unceasingly whileusing the heating device to heat up, so that the nickel powders are meltcompletely and mixed with the magnesium liquid to become a uniformmagnesium-nickel liquid. It is not necessary for the apparatus andmethod according to the present invention to install delicate in-situinspection, nor to control precisely the composition of themagnesium-nickel liquid. It is only required that the weight percentageof the amount of the added nickel to the whole magnesium-nickel melt isbetween 23.5 and 50.2, then it is guaranteed to give pure γ-phase Mg₂Nihydrogen storage alloy with composition of Mg-54.6 wt % Ni (that is, theatomic ratio between magnesium and nickel is 2:1) without other phases.

The next step is to control the heating temperature of the heatingdevice to be within a temperature range, which is between 507° C. and761° C. According to the segregation principle of physical metallurgyand to the Mg—Ni phase diagram, high-purity magnesium-nickel hydrogenstorage alloy will be formed and precipitated automatically, and thepurity thereof is independent of the precipitation temperature withinsaid temperature range. Thereby, according to the present invention, itis not necessary to adopt accurate and costly temperature controlsystems. In addition, the precipitated quantity (weight) of the hydrogenstorage alloy Mg₂Ni depends on the composition of the magnesium-nickelliquid and the precipitation temperature. In general, within the broadranges of composition and temperature conditions according to thepresent invention, the higher the proportion of nickel and the lower theprecipitation temperature, the more the precipitated quantity ofhigh-purity γ-phase Mg₂Ni. The exact precipitated quantity (weight) canbe calculated according to the level rule of phase diagram in physicalmetallurgy.

Because the nickel composition (54.6 wt %) of the precipitatedhigh-purity γ-phase Mg₂Ni according to the present invention is higherthan that of the original magnesium-nickel composition (that is, theweight percentage of nickel is between 23.5 and 50.2), with the progressof precipitation reaction, according to the law of conservation of mass,the composition of the residual magnesium-nickel liquid will become moreand more magnesium-rich. The density of nickel (8.9 g/cm³) is muchgreater than that of magnesium (1.74 g/cm³), therefore, the precipitatedhigh-purity magnesium-nickel hydrogen storage alloy will sink at thebottom of the crucible given that the density of solid-statemagnesium-nickel hydrogen storage alloy is much greater than thespecific weight of the magnesium-nickel liquid. Thereby, pour theresidual liquid in the first crucible after the precipitation reactioninto the second crucible, draw out the first crucible loaded with theprecipitated magnesium-nickel hydrogen storage alloy from the heatingdevice, and cool the first crucible. After cooling, pick out themagnesium-nickel hydrogen storage alloy from the first crucible, andrepeat the procedure described above for the second crucible loaded withthe residual liquid. Then high-purity magnesium-nickel hydrogen storagealloy is given continuously.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a flowchart according to a preferred embodiment of thepresent invention;

FIG. 2A shows a schematic diagram of the apparatus in the steps S10 andS11 according to a preferred embodiment of the present invention;

FIG. 2B shows a schematic diagram of the apparatus in the step S12according to a preferred embodiment of the present invention;

FIG. 2C shows a schematic diagram of the apparatus in the step S13according to a preferred embodiment of the present invention;

FIG. 2D shows a schematic diagram of the apparatus in the step S14according to a preferred embodiment of the present invention;

FIG. 2E shows a schematic diagram of the apparatus in the step S15according to a preferred embodiment of the present invention;

FIG. 2F shows a schematic diagram of the apparatus in the step S16according to a preferred embodiment of the present invention; and

FIG. 3 shows a schematic diagram of the apparatus according to anotherpreferred embodiment of the present invention.

DETAILED DESCRIPTION

In order to make the structure and characteristics as well as theeffectiveness of the present invention to be further understood andrecognized, the detailed description of the present invention isprovided as follows along with preferred embodiments and accompanyingfigures.

FIG. 1 and FIG. 2A show a flowchart and a schematic diagram of theapparatus in the steps S10 and S11 according to a preferred embodimentof the present invention. As shown in the figure, the present inventionprovides a method and apparatus for manufacturing high-puritymagnesium-nickel hydrogen storage alloy. The apparatus comprises avacuum chamber 10 with a material feeding tube 104, a first crucible 12,a heating device 14, a stirring device 16, and a second crucible 18. Byusing the apparatus, the step S10 is executed for putting a raw materialof magnesium 11 into the first crucible 12, where the raw material ofmagnesium 11 is a magnesium metal bulk, and the material of the firstcrucible 12 is a metal material with melting point greater than that ofthe magnesium metal. Then, gas an inert gas 13 into the vacuum chamber10, and put the first crucible 12 with the raw material of magnesium 11into the vacuum chamber 10. Before gassing the inert gas 13 into thevacuum chamber 10, the inert gas 13 is first used to purge the vacuumchamber 10. Finally, seal the vacuum chamber 10, and let the inert gas13 be maintained in the vacuum chamber 10. After the first crucible 11loaded with the raw material of magnesium 11 is put into the vacuumchamber 10, the step S11 is executed for setting the first crucible 12in the heating device 14, which is used for heating the raw material ofmagnesium 11 in the first crucible 12 to be totally melt and become amagnesium liquid 110. The heating device 14 is a resistive heater with atemperature adjustment function.

FIG. 2B shows a schematic diagram of the apparatus in the step S12according to a preferred embodiment of the present invention. As shownin the figure, after the raw material of magnesium 11 in the firstcrucible 12 is melt into the magnesium liquid 110, the step S12 isexecuted for adding nickel powders 15 slowly to the magnesium liquid 110in the first crucible 12 by using the material feeding tube 104, andstirring the magnesium liquid 110 and the nickel powders 15 loaded inthe first crucible 12 by using the stirring device 16. Besides, theheating device 14 is used for heating the first crucible 12 with themagnesium liquid 110 and the nickel powders 15 so that the temperatureof the magnesium liquid 110 is heated above 770° C. Thereby, the nickelpowders 155 are melt completely in the magnesium liquid 110 and auniformly mixed magnesium-nickel liquid 112 is produced. The stirringdevice 16 includes a motor 161 and a paddle 163. In addition, thestirring device 16 can be elevated. When the stirring device 16 is usedfor stirring, the paddle 163 can elevated to a proper position, and themotor 161 will drive the paddle 163 for stirring. Furthermore, anoar-shaped blade 165 is adapted on one end of the paddle 163 forincreasing stirring area and speed. When stirring is performed, thepaddle 163 of the stirring device 16 is retracted. The weight percentageof the nickel element in the magnesium-nickel liquid 112 is between23.5% and 50.2%, which represents the composition of the added nickelpowders. Thereby, the composition ratio of the magnesium and nickelelements in the final precipitated high-purity solid-statemagnesium-nickel hydrogen storage alloy is 2:1 without other phases.

FIG. 2C shows a schematic diagram of the apparatus in the step S13according to a preferred embodiment of the present invention. As shownin the figure, when the magnesium-nickel liquid 112 is produced, thestep S13 is executed for controlling the temperature of the heatingdevice 14 to fall within a temperature range. Thereby, the temperatureof the magnesium-nickel liquid 112 will be within the temperature range,which is above the solidification temperature and below theliquification temperature of the magnesium-nickel liquid 112. That is,between 507° C. and 761° C. According to the segregation principle ofphysical metallurgy and to the Mg—Ni phase diagram, high-puritymagnesium-nickel hydrogen storage alloy 114 will be formed andprecipitated from the magnesium-nickel liquid 112 automatically, and thepurity thereof is independent of the precipitation temperature withinsaid temperature range. Thereby, according to the present invention, itis not necessary to adopt accurate and costly temperature controlsystems. In addition, the precipitated quantity (weight) of the hydrogenstorage alloy 114 depends on the composition of the magnesium-nickelliquid and the precipitation temperature. In general, within the broadranges of composition and temperature conditions according to thepresent invention, the higher the proportion of nickel and the lower theprecipitation temperature, the more the precipitated quantity ofhigh-purity magnesium-nickel hydrogen storage alloy 114. The exactprecipitated quantity (weight) can be calculated according to the levelrule of phase diagram in physical metallurgy.

FIG. 2D shows a schematic diagram of the apparatus in the step S14according to a preferred embodiment of the present invention. As shownin the figure, the solid-state magnesium-nickel hydrogen storage alloy114 is precipitated from the magnesium-nickel liquid 112. The nickelcomposition of the magnesium-nickel hydrogen storage alloy 114 isgreater than that in the magnesium-nickel liquid 112. With the progressof precipitation reaction, according to the law of conservation of mass,the composition of the residual magnesium-nickel liquid 116 will becomemagnesium-rich. The density of nickel (8.9 g/cm³) is much greater thanthat of magnesium (1.74 g/cm³), therefore, the solid-statemagnesium-nickel hydrogen storage alloy 114 will sink at the bottom ofthe first crucible 12. After the magnesium-nickel liquid 112precipitated the solid-state magnesium-nickel hydrogen storage alloy114, the step S14 is executed for separating the residual liquid 116 inthe first crucible 12 from the solid-state magnesium-nickel hydrogenstorage alloy 114 suck at the bottom of the first crucible 12 by pouringthe residual liquid 116 in the first crucible 12 into the secondcrucible 18. In order to pour the residual liquid 116 in the firstcrucible 12 into the second crucible 18 easily, an inclinable base 19 isadapted in the vacuum chamber 10 with the first crucible 12 and theheating device 14 set thereon. When the base 19 inclines, the firstcrucible 12 and the heating device 14 incline with the base 19, and theresidual liquid 116 will be poured into the second crucible 18. Finally,the solid-state magnesium-nickel hydrogen storage alloy 114 will be leftat the bottom of the first crucible 12.

FIG. 2E shows a schematic diagram of the apparatus in the step S15according to a preferred embodiment of the present invention. As shownin the figure, the step S15 is executed. Draw out the first crucible 12from the heating device 14, and cool the first crucible 12 loaded withthe solid-state magnesium-nickel hydrogen storage alloy 114. In or todraw out the first crucible 12 from the heating device 14 conveniently,a hoist mechanism 17 is further adapted in the vacuum chamber 10. Thehoist mechanism 17 includes a plurality of twisted ropes 171, which isfixed on the first crucible 12. Thereby, the hoist mechanism 17 can drawout the first crucible 12 from the heating device 14. In addition, inorder to secure the connection between the hoist mechanism 17 and thefirst crucible 12, a plurality of hanging ears (not shown in the figure)is adapted at the periphery of the opening of the first crucible 12. Ahanging hook (not shown in the figure) is adapted on one end of theplurality of twisted ropes 171 of the hoist mechanism 17, respectively.Thereby, the hanging hooks are hooked on the plurality of hanging earsof the first crucible 12. Thus, the connection between the hoistmechanism 17 and the first crucible 12 is secured.

Another significant technological breakthrough of the present inventionis to recycle the residual liquid, and thereby a method and apparatusfor continuously manufacturing high-purity magnesium-nickel hydrogenstorage alloy is developed. FIG. 2F shows a schematic diagram of theapparatus in the step S16 according to a preferred embodiment of thepresent invention. As shown in the figure, after the first crucible 12is drawn out from the heating device 14, the step S16 is executed forputting the second crucible 18 loaded with the residual liquid 116 intothe heating device 14 by using the hoist mechanism 17. Then, the stepsS10 through S16 are executed repeatedly for continuously manufacturinghigh-purity magnesium-nickel hydrogen storage alloy 114. The first andthe second crucibles 12, 18 are used alternately owing to continuousmanufacturing.

While manufacturing continuously, the second and thereaftermanufacturing cycles differ from the first manufacturing cycle in that,in the second and thereafter manufacturing cycles, in order to increaseproductivity of high-purity magnesium-nickel hydrogen storage alloy 114,the amount of added nickel powders can be increased from the presetrange of 23.5% and 50.2% up to 54.6%. The condition still giveshigh-purity magnesium-nickel hydrogen storage alloy 114 without otherphases. Because the residual liquid 116 is a magnesium-rich liquid,which is an excellent composition adjuster, the nickel composition ofthe magnesium-nickel liquid 112 can be maintained within the range of 20to 55 wt % without precise and accurate control of chemical composition.

FIG. 3 shows a schematic diagram of the apparatus according to anotherpreferred embodiment of the present invention. As shown in the figure,the present invention provides an apparatus for manufacturinghigh-purity magnesium-nickel alloy and comprising a vacuum chamber 10, afirst crucible 12, a heating device 14, a stirring device 16, a secondcrucible 18, a hoist mechanism 17, a water-cooled copper base 100 withrecycling cooling water, and a material feeding tube 104. The vacuumchamber 10 according to the present preferred embodiment is divided intoa precipitation chamber 101 and a crucible in/out chamber 103. One ormore isolation valves 102 are adapted between the precipitation chamber101 and the crucible in/out chamber 103, so that the precipitationchamber 101 can be maintain in vacuum or in the inert gas no matterseparation or crucible in/out is undergoing.

The first crucible 12, the heating device 14, the stirring device 16,the hoist mechanism 17, the water-cooled copper base 100, and thematerial feeding tube 104 are set in the precipitation chamber 101 ofthe vacuum chamber 10. The first crucible is set on the heating device14. The stirring device is set on top of precipitation chamber 101 ofthe vacuum chamber 10, and facing the first crucible 12. The hoistmechanism 17 is also set on top of precipitation chamber 101 of thevacuum chamber 10. The water-cooled copper base 100 is set on one sideof the first crucible 12. The material feeding tube 104 penetrates thevacuum chamber 10.

According to the present invention, place a raw material of magnesium tothe first crucible 12 on the crucible in/out chamber 103 of the vacuumchamber 10, and gas an inert gas to the vacuum chamber 10. Use the hoistmechanism 17 to put the first crucible 12 loaded with the raw materialof magnesium to the precipitation chamber 101 filled with the inert gasand into the heating device 14. The heating device 14 heats the firstcrucible 12 loaded with the raw material of magnesium, melts the rawmaterial of magnesium to a magnesium liquid. Then, through the materialfeeding tube 104 penetrating the vacuum chamber 10, nickel powders areadded into the first crucible 12 loaded with the magnesium liquid. Byusing the heating device 14, the first crucible 12 loaded with thenickel powders and the magnesium liquid. Besides, the stirring device 16is used for stirring, so that the nickel powders are melt in themagnesium liquid to produce a magnesium-nickel liquid. Next, control thetemperate of the heating device 14 to fall within a temperature rangefor the magnesium-nickel liquid to precipitate a solid-statemagnesium-nickel hydrogen storage alloy. Finally, separate the residualliquid in the first crucible from the precipitated solid-statemagnesium-nickel hydrogen storage alloy. First, place a raw material ofmagnesium in the second crucible 18 and put it to the precipitationchamber 101 of the vacuum chamber 10. Use the hoist mechanism 17, whichis capable of inclining, to put the first crucible 12 loaded withresidual liquid to the second crucible 18, and put the first crucible 12on the water-cooled copper base 100 in the precipitation chamber 101.The water-cooled copper base 100 cools the solid-state magnesium-nickelhydrogen storage alloy in the first crucible 12. After cooling, use thehoist mechanism 17 to pick the first crucible 12 out, and take thesolid-state magnesium-nickel hydrogen storage alloy from the firstcrucible 12. The water-cooled copper base 100 is adapted in theprecipitation chamber 101. Because the activity of magnesium-nickelhydrogen storage alloy is very high, it tends to react with oxygen oreven ignite, deteriorating its characteristics and producing dangers, itis necessary to cool sufficiently before drawing out from theprecipitation chamber 101 in vacuum or filled with the inert gas. Inmass production, for example, smelt above hundreds of kilograms or tons,the cooling rate of nature cooling is insufficient, and thus limitingthe production efficiency. Thereby, the water-cooled copper base isequipped in the precipitation chamber 101. By taking advantage of theexcellent heat-sinking characteristic of copper, the first crucibleloaded with high-purity solid-state magnesium-nickel hydrogen storagealloy can be quenched rapidly.

To sum up, the present invention provides a method and apparatus formanufacturing high-purity magnesium-nickel hydrogen storage alloy, whichcan be used for manufacturing high-purity magnesium-nickel hydrogenstorage alloy with superior hydrogen absorption-desorption dynamicswithout the need of adopting costly and delicate equipments. Inaddition, the residual liquid after precipitation reaction can berecycled and high-purity magnesium-nickel hydrogen storage alloy withsuperior hydrogen absorption-desorption dynamics can be manufacturedcontinuously.

Accordingly, the present invention conforms to the legal requirementsowing to its novelty, non-obviousness, and utility. However, theforegoing description is only a preferred embodiment of the presentinvention, not used to limit the scope and range of the presentinvention. Those equivalent changes or modifications made according tothe shape, structure, feature, or spirit described in the claims of thepresent invention are included in the appended claims of the presentinvention.

1. A method for manufacturing high-purity magnesium-nickel hydrogenstorage alloy, comprising steps of: heating a raw material of magnesiumin an inert gas, and melting the raw material of magnesium to amagnesium liquid; adding nickel powders to the magnesium liquid, andstirring and heating the magnesium liquid mixed with the nickel powdersfor melting the nickel powders in the magnesium liquid; producing amagnesium-nickel liquid after the nickel powders are melt in themagnesium liquid; controlling the temperature of the magnesium-nickelliquid to fall within a temperature range, and the magnesium-nickelliquid precipitating a solid-state magnesium-nickel hydrogen storagealloy; and separating the residual liquid from the precipitatedsolid-state magnesium-nickel hydrogen storage alloy, and giving thesolid-state magnesium-nickel hydrogen storage alloy.
 2. The method ofclaim 1, wherein the step of separating the residual liquid from theprecipitated solid-state magnesium-nickel hydrogen storage alloy furthercomprises cooling the solid-state magnesium-nickel hydrogen storagealloy.
 3. The method of claim 1, wherein the composition ratio of themagnesium and nickel elements in the solid-state magnesium-nickelhydrogen storage alloy is 2:1.
 4. The method of claim 1, and furthercomprising a step of heating the separated residual liquid, andrepeating the steps of heating a raw material of magnesium in an inertgas, and melting the raw material of magnesium to a magnesium liquid,adding nickel powders to the magnesium liquid, and stirring and heatingthe magnesium liquid mixed with the nickel powders for melting thenickel powders in the magnesium liquid, producing a magnesium-nickelliquid after the nickel powders are melt in the magnesium liquid,controlling the temperature of the magnesium-nickel liquid to fallwithin a temperature range, and the magnesium-nickel liquidprecipitating a solid-state magnesium-nickel hydrogen storage alloy, andseparating the residual liquid from the precipitated solid-statemagnesium-nickel hydrogen storage alloy, and giving the solid-statemagnesium-nickel hydrogen storage alloy, for continuously giving thesolid-state magnesium-nickel hydrogen storage alloy.
 5. The method ofclaim 1, wherein the raw material of magnesium is a magnesium metalbulk.
 6. The method of claim 1, wherein the weight percentage of thenickel element in the magnesium-nickel liquid is between 23.5% and50.2%.
 7. The method of claim 1, wherein the temperature range isbetween 507° C. and 761° C.
 8. The method of claim 1, wherein theresidual liquid is a magnesium-rich liquid.
 9. An apparatus formanufacturing high-purity magnesium-nickel hydrogen storage alloy,comprising: a vacuum chamber, comprising a material feeding tube; afirst crucible, set in the vacuum chamber; a heating device, set on thefirst crucible; a stirring device, set in the vacuum chamber, and abovethe first crucible; and a second crucible, set in the vacuum chamber,and on one side of the first crucible.
 10. The apparatus of claim 9,wherein the material of the first crucible and the second crucible is ametal material with a melting point exceeding that of magnesium.
 11. Theapparatus of claim 9, wherein manufacturing high-purity magnesium-nickelhydrogen storage alloy comprises placing a raw material of magnesium tothe first crucible, gassing an inert gas to the vacuum chamber, heatingthe first crucible loaded with the raw material of magnesium by theheating device, melting the raw material of magnesium to a magnesiumliquid, adding nickel powders to the first crucible loaded with themagnesium liquid by using the material feeding tube, heating the firstcrucible loaded with the mixed powders and the magnesium liquid by usingthe heating device, stirring by using the stirring device to make thenickel powders melt in the magnesium liquid and produce amagnesium-nickel liquid, controlling the heating temperature of theheating device to fall within a temperature range, precipitating asolid-state magnesium-nickel hydrogen storage alloy from themagnesium-nickel liquid, separating the residual liquid in the firstcrucible from the precipitated solid-state magnesium-nickel hydrogenstorage alloy, pouring the residual liquid in the first crucible to thesecond crucible, cooling the magnesium-nickel hydrogen storage alloy inthe first crucible, and drawing out the magnesium-nickel hydrogenstorage alloy from the first crucible after cooling.
 12. The apparatusof claim 11, wherein cooling the magnesium-nickel hydrogen storage alloyin the first crucible is drawing out the first crucible from the heatingdevice, and picking out the magnesium-nickel hydrogen storage alloy fromthe first crucible after cooling.
 13. The apparatus of claim 11, and themanufacturing high-purity magnesium-nickel hydrogen storage alloyfurther comprising setting the second crucible in the heating device andadding a raw material of magnesium for heating, melting into a magnesiumliquid, adding nickel powders by using the material feeding tube,heating by using the heating device, stirring by using the stirringdevice to make the nickel powders melt in the magnesium liquid andproduce a magnesium-nickel liquid, controlling the heating temperatureof the heating device to fall within a temperature range, precipitatinga solid-state magnesium-nickel hydrogen storage alloy from themagnesium-nickel liquid, separating the residual liquid in the secondcrucible from the precipitated solid-state magnesium-nickel hydrogenstorage alloy, pouring the residual liquid in the second crucible to thefirst crucible, cooling the magnesium-nickel hydrogen storage alloy inthe second crucible, and drawing out the magnesium-nickel hydrogenstorage alloy from the first crucible after cooling.
 14. The apparatusof claim 11, wherein before gassing the inert gas into the vacuumchamber, the inert gas is used first to purge the vacuum chamber. 15.The apparatus of claim 14, wherein after the inert gas is gassed intothe vacuum chamber, seal the vacuum chamber.
 16. The apparatus of claim9, wherein the heating device is a resistive heater.
 17. The apparatusof claim 9, wherein the vacuum chamber further includes a precipitationchamber and a crucible in/out chamber.
 18. The apparatus of claim 17,wherein one or more valves are set between the precipitation chamber andthe crucible in/out chamber, so that the precipitation chamber can bemaintain in vacuum or in the inert gas when separation or cruciblein/out is undergoing.
 19. The apparatus of claim 11, and furthercomprising a base, set at the bottom of the heating device and the firstcrucible, inclining the first crucible and the heating device so thatthe first crucible can pour the residual liquid to the second crucible.20. The apparatus of claim 11, and further comprising a hoist mechanism,set in the vacuum chamber for hanging the first crucible into or out ofthe heating device.
 21. The apparatus of claim 20, wherein the hoistmechanism includes a plurality of twisted ropes one side fixed on thefirst or the second crucible, and inclining one side of the first or thesecond crucible.
 22. The apparatus of claim 21, wherein the a pluralityof hanging ears is set at the periphery of the opening of the firstcrucible and corresponds to the plurality of twisted ropes on the hoistmechanism, and a hanging hook is set on one end of the plurality oftwisted ropes of the hoist mechanism, respectively, so that the hanginghooks are hooked on the plurality of hanging ears, and one end of theplurality of twisted ropes is secured on the first or second crucible.23. The apparatus of claim 9, wherein the stirring device includes amotor and a paddle with the motor driving the paddle for stirring. 24.The apparatus of claim 23, wherein an oar-shaped blade is set on one ofend of the paddle.
 25. The apparatus of claim 11, wherein the vacuumchamber further comprises a water-cooled copper base equipped withrecycling cooling water for cooling the first crucible loaded with thesolid-state magnesium-nickel hydrogen storage alloy.
 26. The apparatusof claim 11, wherein before separating the residual liquid in the firstcrucible and pouring the residual liquid to the second crucible, a rawmaterial of magnesium can be added to the second crucible.
 27. Theapparatus of claim 26, and the manufacturing high-puritymagnesium-nickel hydrogen storage alloy further comprising setting thesecond crucible in the heating device and adding a raw material ofmagnesium for performing heating, stirring by using the stirring deviceto make the nickel powders melt in the magnesium liquid and produce amagnesium-nickel liquid, controlling the heating temperature of theheating device to fall within a temperature range, precipitating asolid-state magnesium-nickel hydrogen storage alloy from themagnesium-nickel liquid, separating the residual liquid in the secondcrucible from the precipitated solid-state magnesium-nickel hydrogenstorage alloy, pouring the residual liquid in the second crucible to thefirst crucible, cooling the magnesium-nickel hydrogen storage alloy inthe second crucible, and drawing out the magnesium-nickel hydrogenstorage alloy from the first crucible after cooling.